Relatively small casing for a high speed miniature centrifuge



March 15, 1966 F. E. RAY ETAL 3,240,425

RELATIVELY SMALL CASING FOR A HIGH SPEED MINIATURE GENTRIFUGE Filed June '7, 1962 5 Sheets-Sheet 1 INVENTORS FPA'D 5. PA/

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March 15, 1966 F. E. RAY ETAL RELATIVELY SMALL CASING FOR A HIGH SPEED MINIATURE CENTRIFUGE Filed June 7, 1962 5 Sheets-Sheet 2 FIG. 3

March 15, 1966 F. E. RAY ETAL RELATIVELY SMALL CASING FOR A HIGH SPEED MINIATURE CENTRIFUGE 5 Sheets-Sheet 3 Filed June '7, 1962 mum V mm ad W C, W? mjp 2 04 7 5 7 MM 0 (DQU FIG. 5

March 15, 1966 RAY ETAL RELATIVELY SMALL CASING FOR A HIGH SPEED MINIATURE CENTRIFUGE 5 Sheets-Sheet L Filed June 7, 1962 Qb NW WW E: Q N QN INVENTORS. [95D PAY EM/[ /4- .sCaRDATO March 15, 1966 F. E. RAY ET AL 3,240,425

RELATIVELY SMALL CASING FOR A HIGH SPEED MINIATURE CENTRIFUGE Filed June '7, 1962 5 Sheets-Sheet 5 WI" I 250' HII H INVENTORS. 6. A24 y 6114/4 ,4. scaeanra BY 61440 14 14 04::

a 44m ZQ United States Patent RELATIVELY SMALL CASING FOR A HIGH SPEED MINIATURE CENTRIFUGE Fred E. Ray, Ramsey, N.J., Emil A. Scordato, Bronxville,

1 LY., and Gerald W. Wolfe, Santa Monica, Calif., asslgnors to Becton, Dickinson and Company, Rutherford, N.J., a corporation of New Jersey Filed June 7, 1962, Ser. No. 200,739 Claims. (Cl. 233-1) This invention relates to a centrifuge casing and, more particularly, to a casing for a relatively light weight, miniature centrifuge capable of rotating at high speeds separating liquid materials into their constituent parts Within short periods of time.

In centrifuging liquid materials for separating into constituent parts, a rotating head may be provided for receiving the selected liquid material to subject it to centrifugal forces of magnitudes capable of causing the desired separation. The head would normally be driven at relatively high speeds; and numerous safety precautions are required in order to protect attending personnel. Incident to centrifuge use, safety precautions should be present not only during actual centrifugation, but at all times, including protection when the centrifuge is in nonuse; therefore, measures should be taken to assure only deliberate initiation of operation of the centrifuge. At the same time, the construction of the centrifuge should be such to facilitate the introduction and removal of the liquid material prior to and subsequent to operation, respectively. Furthermore, the rotating head should be readily removable for maintenance, as well as cleansing operations. It is also desirable to permit the liquid material to be viewed during centrifug-ation to observe the separation taking place. Needless to say, provisions should be made to prevent accidental release during centrifugation of the liquid material to be separated. Precautionary measures should be taken to prevent uncontrolled separation during centrifugation which may result in throwing or splattering of the material being subjected to centrifugal forces.

It is, therefore, a principal object of the present invention to facilitate the foregoing by providing a casing for a centrifuge which permits the centrifuge to be compactly incorporated therein within detrimentally affecting the intended centrifuge operation and, at the same time, provide a portable miniature structure.

Another object is to provide a centrifuge casing having means for assuring the initiation of operation of the centrifuge only at such time as the centrifuge is properly loaded with the liquid material to be separated and possessing a protective enclosing position at which, and, only at which, the centrifuge operation will commence.

Still another object is to provide a centrifuge casing having means for cooperating with the centrifuge for facilitating the detachment and complete removal of the centrifuge head.

A further object is to provide a centrifuge casing having means for initiating the operation of the centrifuge, only when intended.

A still further object is to provide centrifuge casing having means for positively enclosing the centrifuge head and, at the same time, enabling it to be readily accessible to permit introduction of the material to be separated and removal of its separated constituents following centrifugation.

A principal object of the present invention is to provide a centrifuge casing having means for enabling the centrifuge to be employed as a module, singly or together with other units, capable of similar modular use whether they be another like centrifuge or a functionally distinct unit, all of which may contribute to a desired result; as

"ice

for example, in prothrombin and coagulation time determination, the centrifuge module would be employed for purposes of providing pure plasma from whole blood, and a coagulation timer module may conveniently be utilized therewith to detect initial clot formations following the introduction of a sample of the plasama into a particular chemical reagent.

A casing for a centrifuge constructed in accordance with the teachings of the present invention includes a base from which extends vertically, in an upward direction, a body having four side walls defining a parallelogram in cross-section. A pivotal cover is hingedly mounted on the body from a closed position at which centrifugation is intended to occur to an open position to provide access to the casing interior. Thus, in the latter case the intended operation may be accomplished whether it be loading and unloading of a centrifuge head with liquid material, removal or remounting of the centrifuge head, or the performance of any maintenance or repair work as needed.

Within the casing a relatively high speed motor is securely mounted in a manner to be substantially free from vibration and, at the same time, sufiiciently isolated to dampen and even prevent induced vibrations during motor operation. A centrifuge head is coupled with the outputshaft of the motor through a releasable locking mechanism which permits removal of the head and remounting as desired. In this connection, the casing includes a pressure plate therein to facilitate the actuation of the releasable locking mechanism when the cover is in an open position to enable the head to be removed without difficulty.

The cover, as stated, is pivotally hinged to the casing body and, under these circumstances, is adapted to be latched securely in its closed position over the body side walls. To this end, a latch assembly is provided between the cover and the body and includes interengaging parts capable of the latching function. An arm projects outwardly from the cover and is adapted to be manually actuated to release the latch when it is desirable to pivot the cover to its open position.

When the centrifuge head has been loaded with the material to be separated and the cover placed in its closed position, a shiftable pressure bar, constituting part of the casing will be in engagement with an interiorly mounted start-stop switch for the motor and adapted to be depressed to energize the motor. A rather inaccessible switch is incorporated in the casing body for closing and breaking the circuit of the motor and its switch. In this connection, projecting portions of the cover are adapted to close the safety switch only when the cover is in its closed latched position for assurance against inadvertent actuation of the motor switch.

The cover and body are also interconnected with a link assembly which permits the cover to be readily pivoted from its open to closed position, but will prevent the cover from extending beyond a certain point as it approached the desired open position. The cover is also provided with a transparent cap which perm-its the centrifuge operator or attendant to view the centrifuge head and its contained liquid material to be separated during centrifugation. In addition, this cap acts as a shield in completing the encasement of the centrifuge within the casing.

The casing, with contained centrifuge is relatively compact requiring a minimum number of parts, all of which lend themselves to portable, light-weight miniaturization without sacrificing effective high speed centrifugation within a minimum of time. The casing is so constructed to serve as an individual module readily coupled With a second centrifuge also of modular form. On the other hand, the centrifuge module may be part of a system of modular units conveniently arranged and coupled with respect to one another, as well as designed to provide.

maximum arrangement and flexibility depending upon the intended use and application.

As will be explained in detail, a preferred application of the centrifuge is in prothrombin time determinations and measurements of coagulation properties of plasma in diagnostic and therapy control. With this in mind, a laboratory or clinic for such purposes may be comprised of modular units readily coupled with one another which may also include a coagulation timer and heater block forming part of a laboratory. In view of the modular nature of the system, the individual modules can be employed whether the laboratory be large or small. Furthermore, the miniature size and portable nature of the individual modules, of which the centrifuge forms a part, can be carried and most advantageously utilized by any physician at a patients bedside.

Other objects and advantages will become apparent from the following detailed description which is to be taken in connection with the accompanying drawings illustrating a somewhat preferred embodiment of the invention, it being understood, however, that the scope of the present invention is not necessarily limited thereby.

I FIG. 1 is a perspective view of the casing of the present'invention having mounted therein a centrifuge shown in association with another like unit illustrating the versatility of the modular system contemplated, with one of the centrifuge units coupled with a coagulation timer shown in phantom;

' FIG. 2 is another perspective view of a casing of the present invention mounting a centrifuge, with the cover of the casing shown in a partially opened position;

FIG. 3 is an enlarged elevational View, sectioned through the casing, with the cover in a closed latched position with certain parts broken away and removed for clarity;

FIG. 4 is a sectional view taken along the line 44 of FIG. 3;

FIG. 5 is a sectional view taken along the line 55 of FIG. 3;

FIG. 6 is a fragmentary sectional view taken along line 66 of FIG. 5, showing the link assembly in open position, with its closed position being shown by way of dotted lines;

FIG. 7 is a fragmentary sectional view taken along line 77 of FIG. 5, showing the safety switch with associated casing structure,

FIG. 8 is a fragmentary sectional view taken along line 8-8 of FIG. 3 showing the cover latching assembly; and

FIG. 9 is a fragmentary sectional view taken along line 9 '-9 of FIG. 3 showing the motor mounting.

In the drawings, a centrifuge 10 is shown disposed within a casing 12 in accordance with the teachings of the present invention. As depicted in ,FIG. 1, a modular system is contemplated whereby the casings, together with their contained centrifuge, may be disposed side by side for operation, together with a further modular unit 14 in accordance with the dictates of the particular system. The centrifuge 10 may be of a type which includes a centrifuge head assembly 16 releasably anchored to a relatively high speed motor 18 by means of a locking assembly 20. The details of construction and operation of the particular centrifuge 10 are disclosed in companion patent application entitled Improved Centrifugation Apparatus and Method, filed on May 7, 1962 under Serial No. 192,709 in which a common interest is present. Suffice it to say that the centrifuge 10 is of a reduced size rendering it conveniently portable. One of the applications of the centrifuge 10 is in the area of blood separationfor prothrombin time determinations and measurements of the coagulation properties of plasma in diagnostic and therapy control. Thus, the centrifuge 10 would be of advantage in clinical and medical laboratory use. The relative ease in handling and carrying the 4- centrifuge permits physicians to utilize it at the bedside of a patient.

The centrifuge head assembly 16 is provided with a cavity for the reception of whole blood. Upon rotation of the head, the contained blood will be exposed to centrifugal forces. The heavier red and white blood cells and platelets under these circumstances will separate from the lighter plasma of the blood. After a given period of rotation, separation will be complete. The head speed is then reduced through the de-energization of the motor 18. Shortly thereafter shiftable means within the head assembly 16 will react to the reduction in centrifugal force to seal off a major portion of the pure plasma from the heavier blood constituents. The sealed relationship subsists after cessation of rotation such that the lighter constituents, notably plasma, may now be removed through the use of conventional aspirating devices.

In order to reload the centrifuge the separated blood need only be removed. In this connection, a disposable bag may be utilized to contain the blood within the head cavity. Thus, after separation, the bag with separated blood would be removed and replaced with a fresh bag into which a new sample of blood to be separated is introduced. The centrifuge operation may then be repeated on the fresh blood sample. As disclosed in the companion application, the head assembly would measure approximately 1 /2 inches in diameter; and the ca pacity of the bag would be in the neighborhood of a few milliliters.

The releaseable locking assembly 20 permits the head assembly 16 to be quickly disconnected from the output shaft of the motor 18 and, at the same time, enables the head to rotate with the shaft during operation. The locking assembly includes, among other parts, a radial flange 22 which may be engaged and shifted downwardly. As disclosed in the above application, this would have the effect of unlocking the head assembly 16 and thereby permit it to be lifted off the drive shaft.

Since one of the primary uses of the centrifuge 10 is to provide pure plasma quickly and conveniently for test procedures to follow, the motor 18 should be capable of high speed output. For this reason the speed capabilities of the motor 18 will range from about 15,000 to 20,000 rpm.

Referring now to the casing 12, it will be observed that the centrifuge 10 is conveniently accommodated therein for eflicient operation. Thus, the casing 12 includes a base 24 on which the motor 18 rests. A body 25 is anchored to the base 24 and includes upwardly extending vertical side walls 26 and 28, front wall 30 and rear wall 32. A cover 34 is pivotally mounted on the body 24 from a closed position at which the centrifuge 10 is operated to an open position at which the centrifuge is preferably inoperable. Thus, in the latter position, the .material to be separated may be introduced into the centrifuge head assembly 16 and following separation through centrifugation, the material may be removed therefrom. When the cover 34 is in its open position, the head assembly 16 may also be advantageously removed through the actuation of the locking assembly 20 to permit cleansing, maintenance or repair if needed.

The base 24, under the circumstances, will include a vertical front panel 40 and vertical rear panel 42 both of which are integral with a substantially horizontal wall 44 having an elevated wall portion 46. The wall portion 44 is provided with a bore 48 and enlarged coaxial counter-bore 50 for receiving downwardly projected parts of the motor 18. A series of resilient pads 52 may be strategically located on the bottom of the base at favorable locations to provide a cushioning effect and, at the same time, preventing marring of the surface on which the casing is placed.

A number of screws 56 extend through the base 24 and threadedly engage with openings in the body 25 to secure these parts to one another. In this connection, a resilient grommet 58 extends around openings 60 in the base 24 through which the screws 56 project. As will be appreciated, these grommets 58 are employed for purposes of minimizing surface to surface con-tact of these parts and, consequently, the transmission of vibrations therebetween. A cylindrical spacer 62 surrounds the threaded shank of the screw 56 and is adapted to engage with the screw head as well as surfaces of the plate 74. Accordingly undue penetration of the screw 56 into the plate 74 is prevented, as well as possible damaging compression and distortion of the grommet 58.

The motor 18 includes the usual downwardly extending anchor bolts 66 which are adapted to project through suitably formed openings 68 in the wall 44 of the base 24 when the motor is seated thereon. Mating nuts 78 engage with the threaded bolts to completely anchor the motor 18 to the base 24.

The side walls 26 and 28 of the body 25 are substantially rectangular and planar in configuration. These side walls are spaced from one anotherin substantially parallel relationship and are interconnected by means of an integral transverse plate 74 extending therebetween. The plate 74 is provided with a corresponding number of tapped openings 76 for threadedly receiving the screws 56 in anchoring the base 24 to the body 25. The plate 74 is also provided with an adequate size opening 78 for sufficiently clearing surfaces of the motor 18. A fuse holder 80 may be carried by the plate 74 to mount a suitably rated fuse for the motor 18. In this connection, the elevated wall portion 46 of the base 24 may be supplied with an adequate opening 82 for the insertion and removal of a fuse.

The front wall and a rear wall 32 are likewise substantially planar and spaced from one another in parallel relationship. A horizontal plate 90 extends transversely therebetween and is integrally formed therewith for maintaining this relationship. In addition, inwardly extending integral enlarged corners 92 are situated along each of the respective vertical edges of the front wall 30 and rear wall 32 below plate 90. These corners are each provided with a tapped opening 94 for mating with screws 96 also extending through suitably countersunk openings 97 of the plate 74 for interconnecting the body side walls. The rear wall 32 above plate 91) is provided with integral flanges 98 and 99 extending inwardly therefrom. The plate 90 includes an enlarged opening 188 for accommodating, with sufiicient clearance, the upper part of the motor 18. The plate 90, along the periphery of this opening, is formed with a downwardly projecting rim 102 having a somewhat conical inner face 164. A space is accordingly provided between this face and surface of the motor 18 so that a resilient ring 106 is adapted to be interposed therebetween to mechanically isolate the motor from plate 90 and, at the same time, reduce vibration incident to motor operation.

As mentioned in the foregoing, the present invention contemplates means for facilitating the depression of portions of the releasable locking mechanism 28 in order that the head assembly 16 may be removed once the cover 34 is in an unlatched open position. This assumes the form of a pressure plate 110 having downwardly extending peripheral apron 112. An opening 114 is formed in the plate and is of a size sufficient to clear surfaces of the locking mechanism 20. The circular symmetry of the opening 114 is interrupted by a pair of radially inwardly extending tongues 116 also clearing surfaces of the locking assembly 20; but at the same time, these tongues are however adapted to engage with the radial flange 22 thereof when the plate 114 is depressed upon the application of pressure in a downward direction, to correspondingly shift the associated parts of the locking mechanism 20.

The plate is biased vertically by means of a pair of springs 128 extending between the bottom surfaces of the plate 110 and upper face of the plate 90. Screws 121 project through each of the springs 128 into threaded openings 124 in the plate 90. surround each of the screws and rest on the upper face of the plate 90. The spacers also engage with washers 128 disposed between the head of the associated screw and the upper face of the plate 110. Thus, it will be apparent that the spring will bias the plate 110 in an upward direction away from the flange 22 and, at the same time, will limit the amount of vertical movement of the plate 118 to assure adequate spacing between the plate and the flange 22.

The plate 118 is also pivotally mounted on pin 130 secured to flanges 98 and 99 of the rear wall 32. Spacers 132 are mounted on the pin 138 and serve to space the associated sides of plate 110 from these flanges.

A switch 134 is suspended on the plate 98 by means of a suitable mounting bracket 136 so that its actuation pin 138 extends vertically and projects beyond the upper face of the plate 98. As will be explained shortly, the actuation pin 138 is adapted to be depressed, thus energizing the motor 18 when the cover 34 is in its closed position.

A safety switch 144 is also mounted within the casing 12 and serves to maintain the circuit of the motor 18 and switch 134 open until such time as the cover 34 is in its latched and closed position. To this end, the switch 144 is mounted by an angle bracket 146 :so that its actuation button 148 projects through the bore 158 of the plate 90. In order to protect the button 148 from inadvertent contact and assure energization of the motor 18, only when the cover 34 is closed, an upwardly projecting rim 152 surrounds the upper end of the button 148. A downwardly projecting pin 154 on the cover 34 is adapted to be aligned with the button 148, and subsequently depress it to actuate the switch 144 as the cover 34 is lowered to its closed position.

Referring now to the cover 34, it will be observed that a generally flat planar panel extends into a raised configuration defined by four trapezoidal shaped inclined panels 162, 164, 166 and 168, whose trapezoidal walls are integral and symmetrically disposed. The upper periphery of these walls is integrally connected by means of the substantially horizontal panel 170 which may possess a slight curvature, as shown.

The cover 34 is pivotally mounted on the body 25 by means of an elongated hinge pin 184 having its ends fixed in the side walls 26 and 28 of the body 25. The panel 168 is formed with a somewhat rectangular central cutout portion 186 embraced along two opposed edges by side panel portions 188 and 190, both of which terminate at their free ends in enlarged tubular portions 192 and 194, respectively. These enlarged tubular portions are respectively provided with apertures 196 and 198 which are adapted to freely receive the hinged pin 184. Under these circumstances, the cover 34 is adapted to pivot about the pin 184 from its open to closed position.

With respect to the open position, a link assembly 280 is incorporated into the structure to limit the extent to which the cover 34 may be pivoted when opened. Accordingly, link assembly 200 includes an arm 202 having one end pivotally mounted to the cover by means of the pivot screw 204. The threaded shank of which is disposed in a tapped opening 206 of the downwardly projecting flange 207 of the cover 34. A preloaded spring 208 between the associated end of the arm 202 and head of the screw 204 serves to supply resistance to the pivotal movement of the cover 34 to the extent that the cover must be deliberately shifted in its full traverse from open to closed position and back again. The other end of the arm 202, on the other hand, is pivotally mounted on the inwardly extending flange 98 of the rear wall 32 by means of a headed pivot pin 210. This pin 210 together with Cylindrical spacers 126 Y its head is adapted to ride in the elongated double slot 212 of this flange; and the slot 212 is of sufficient length to permit this movement of the pin throughout the full pivotal movement of the cover from open to closed positions. An interposed resilient washer 214 acts as a spacer and facilitates the intended movement of the associated end of the arm 202 and pin 210.

The amount of movement of the cover 34 as it approaches its open position is limited by means of a stop pin 220 which is adapted to engage with the arm 202. This pin projects from the panel 160 of the cover and may be adjusted depending upon the desired open position for the cover 34 which, in the disclosed embodiment, would result in the panel 160 being in a substantial horizontal position.

In the closed position the cover 34 is adapted to be latched to the body 25; and, with this in mind, a latch assembly 226 is conveniently interposed between the body and the cover. Thus, a vertical plate 223, having a lip 230, is secured in the vertical leg of an angle bracket 232 anchored to the plate 90 of the body 25. A suitable slotted opening 234 is provided in the pressure plate 110 to permit the latch plate 228 to project therethrough. A latch plate 236, having a lip 238, is pivotally mounted within the cover 34 by means of a pair of pivot pins 240 and 242. A pair of spring plates 244 and 246 are secured to the latch plate 236 at one end, with their ends being bent to facilitate engagement with the inner face of the trapezoidal wall 166 of the cover 34. An arm 248 extends transversely from the latch plate 236 in an outward direction through a conveniently located slot 250 in the trapezoidal wall 166. Accordingly, when the arm 248 is shifted inwardly and the cover is in its closed position, the engaging lips 230 and 238, which are otherwise latched, will be forced out of engagement against the bias of the springs 244 and 246. The cover 34 at such time need only be lifted and then pivoted to its fully open position at which the arm 202 will come to rest against the stop pin 220. When the cover 34 is to be shifted back to its closed position, the engaging lips 230 and 238 will relatch as the plate 236 cams against plate 228 under the bias of the springs 244 and 246.

The cover is additionally provided with a somewhat circular central opening 256 in its top panel 170. A transparent cap 258 formed from a suitable resinous material such as Lucite is secured across this opening to permit the centrifuge user or attendant to view the liquid contents of the head 16 during centrifugation.

As mentioned in the foregoing, means are conveniently located as part of the cover 34 to facilitate the actuation of the switch 134. In this connection, a pressure bar 260 is also pivotally mounted on the pin 184. When the cover 34 is in its closed latched position the bar 260 will be substantially co-planar with the cover panel 160 and coincidentally, will have its under face resting on the actuation pin 138. Thus, the attendant need only apply pressure to the bar 260 to depress the pin 138 to actuate the switch 134 and consequently energize motor 18. As will be appreciated, this bar 260 will remain in this position resting on the pin 138 notwithstanding the unlatching of the cover 34 and pivoting it to its fully open position.

The modular aspects of the present invention are most effectively attained by locating a female electrical plug 266 and male electrical plug 268 on the body side walls 26 and 28, respectively. Each of these plugs 266 and 268 are secured in place by means of a retaining ring 270 and bracket 272 anchored to the plate 74 The female plug quite obviously will serve to connect the particular centrifuge 10 to a source of electrical energy The male plug, on the other hand, could be inserted into the female plug of another centrifuge or other unit forming part of the modular system which in the case of prothrombin time determination may be a coagulation timer 14 or a heating block unit In utilizing the teachings of the present invention the cover 34 of the casing 12 is first placed in its opened position at which arm 202 will rest on stop pin 220. An electrical connection between the female plug 266 and a source of electrical energy will be assumed throughout this discussion. While the centrifuge 10 may be employed in the centrifugation of various liquid materials and solutions, it is particularly applicable to the separation of blood. In this connection the centrifuge is adapted to provide pure plasma quickly and conveniently for testing as, for example, in prothrombin and coagulation time determinations. With this in mind, a measured quantity of whole blood is now introduced into the centrifuge head 16 in a manner which may assume that disclosed in the above referenced companion patent application. In this connection, the measured quantities contemplated would be in the order of approximately 2 ml. After the centrifuge head 16 has been properly loaded with the selected blood sample, the cover 34 is then pivoted to its closed position about the pivot pin 184. The lips 230 and 233 Will accordingly engage and latch the cover in place. Simultaneously with the latching of the cover 34, the pin 154 will depress the actuating button 148 of the safety switch 144. The motor 18 is now energized by merely pressing downwardly on bar 260 to depress the pin 138 to close the switch 134 and, consequently, complete the circuit to the motor. The head 16 will immediately begin its period of rotation. As the head 16 rotates, constituents of the blood possessing higher specific gravities will move radially outwardly and replace those of lower specific gravity. The heavier red and white blood cells and platelets will accumulate at the radial periphery of the cavity, Whereas the much lighter plasma will predominate the inner central confines of the cavity. After a given period of rotation, when complete separation has occurred, the motor 18 isdeenergized, thereby resulting in deceleration and reduction of the rotational speed of the head 16. The point at which the motor is deenergized may be ascertained by viewing this separation through the transparent cap 258 and then depressing the bar 260 to open the switch 138 and thereby the circuit to motor 18. On the other hand, the cycle may be governed by conveniently located timing means either incorporated Within the casing 12 or located exteriorly thereof. As disclosed in the above identified application, the plasma is sealed from the heavier blood constituent upon the diminution of the centrifugal force incident to deceleration. This sealed relationship will continue after the head rotation has stopped. It has been found in the embodiment of the invention under consideration, that the complete centrifugation cycle for whole blood will take between 15 to 20 seconds for satisfactory results to be realized.

When the head 16 has come to a complete stop the cover 34 is unlatched by pressing inwardly on the arm 248 to disengage the lips 230 and 238 of the latch assembly 226. The cover 34 is then pivoted about its hinge pin 184 to its fully open position, at which the link arm 202 rests on the stop pin 220. At this point the pin 154 will now be removed from engagement with the switch button 148 to open the safety switch 144. The pure plasma may now be applied particularly for test purposes by merely remov- 1ng the desired quantities from the containing cavity of the centrifuge head 16 by employing conventional devices which may include syringes, pipettes, and the like.

When it is desired to reload the centrifuge in order to perform another separation, the already separated blood would first be removed from the centrifuge head cavity and replaced by a fresh blood sample. The centrifuge cycle may at this time be repeated.

In the event that it is desired to remove the centrifuge head 16 for any reason, and while the cover 34 is in its open position, the pressure plate need only be depressed. Under these circumstances, the plate will engage flange 22 of the locking mechanism 20 and force it downwardly to permit the head to be lifted and removed from the driving connection with the output shaft of the motor 18. The construction and operation of a suitable connection is disclosed in the above-identified application.

Thus, it should be readily apparent to those skilled in the art that a relatively light-weight, miniature centrifuge with casing is contributed to the art by the present invention. Rapid separation of samples of liquid materials is provided thereby; and collection of the separated constituents Within a minimum amount of time is possible. The size and structural characteristics of the casing with contained centrifuge permits portability and enables the centrifugation operation to be performed at any desired location. In the case of blood separation, in order to secure pure plasma quickly, the unit may be conveniently utilized at a patients bedside. In this connection, the unit is of such a nature that it can be carried in an ordinary physicians bag to such locations. Needless to say, safety in operation of the centrifuge as supplied by the protective casing enables untrained and trained personnel to practice the invention with equal proficiency. The adaptation of the present invention to a modular system for diagnostic and control work should be fully realized. In this connection the versatility and flexibility of use and location of a modular unit in clinical and laboratory layouts is increased manifold. There is thusly no appreciable restrictions as to space requirements other than requisite surface area and proximity of an electrical convenience outlet.

Thus, among others, the several aforenoted objects and advantages, among others, are most effectively attained. Although only a single preferred embodiment of the invention has been disclosed and described in detail herein, it should be understood that the present invention is in no sense limited thereby, and its scope is to be determined by that of the appended claims.

We claim:

1. A relatively small casing for a high speed miniature centrifuge comprising: a base; side walls extending upwardly from the base; a cover; pivotal means for pivotally mounting said cover on said side walls between a closed position and an open position; a centrifuge in said casing; centrifuge mounting means for mounting said centrifuge in the casing whereby said casing with centrifuge is lightweight and portable; a latch means coupled with said cover and said side walls and extending therebetween to latch said cover to said side walls when said cover is in said closed position; arm means coupled with said latch for actuating said latch to unlatch said cover from said walls so that said cover is permitted to be pivoted to said open position; and a link assembly coupled with said cover and said side walls and extending therebetween permitting said cover to be pivoted between said open and closed position, and means including surfaces of said link assembly and portions of the cover for cooperating to provide a stop for determining said open position and preventing said cover from being pivoted beyond said open position from said closed position.

2. The invention in accordance with claim 1 wherein transparent means forms part of said cover for permitting the centrifuge to be viewed during operation.

3. The invention in accordance with claim 1 wherein a switch means is on the casing for starting and stopping the operation of the centrifuge, and pressure bar means forms part of said cover for actuating said switch means.

4. The invention in accordance with claim 3 wherein safety means is provided for preventing the operation of the centrifuge by the actuation of the switch means when said cover is in an open position and permitting the operating of the centrifuge by said switch means when the cover is in a closed position.

5. A casing for a centrifuge comprising: a base; side walls extending upwardly from the base; a cover; pivotal means for pivotally mounting said cover on said side Walls between a closed position and an open position; a centrifuge in said casing; centrifuge mounting means for mounting said centrifuge in the casing; a latch means coupled with said cover and said side walls and extending therebetween to latch said cover to said side walls when said cover is in said closed position; arm means extending from said cover for actuating said latch to unlatch said cover from said walls so that said cover is permitted to be pivoted to said open position; pivotal means coupled with said cover and said side walls and being therebetween for permitting said cover to be pivoted between said open and closed position; means including surfaces of portions of the cover for cooperating to provide a stop for determining said open position and preventing said cover from being pivoted beyond said open position from said closed position; a switch means on the casing for starting and stopping the operation of the centrifuge; pressure bar means forming part of said cover for actuating said switch means; safety means for preventing the operation of the centrifuge by the actuation of the switch means when said cover is in an open position and permitting the operating of the centrifuge by said switch means when the cover is in a closed position; and said safety means includes a second switch and said centrifuge includes a motor, a circuit electrically connecting said switches and said motor, and said second switch having a button proximate said cover adapted to be engaged by surfaces of the cover to actuate said second switch when said cover is in said closed position and said button is adapted to be disengaged with the surfaces of the cover when the cover is in said open position.

6. A relatively small casing for a high speed miniature centrifuge comprising: a base; side walls extending upwardly from the base; a cover; pivotal means for pivotally mounting said cover on said side walls between a closed position and an open position; a centrifuge in said casing; centrifuge mounting means for mounting said centrifuge in the casingwhereby said casing with centrifuge is lightweight and portable; a latch means coupled with said cover and said side walls and extending therebetween to latch said cover to said side walls when said cover is in said closed position; arm means coupled with said cover for permitting actuation of said latch to unlatch said cover from said walls so that said cover is permitted to be pivoted to said open position; pivotal means coupled with said cover and said side walls and being therebetween permitting said cover to be pivoted between said open and closed position, means including surfaces of portions of the cover for cooperating to provide a stop for determining said open position and preventing said cover from being pivoted beyond said open position from said closed position; and a biased pressure plate mounted within the casing which, upon actuation, engages with and shifts surfaces of the centrifuge to permit removal of parts of the centrifuge when said cover is in said open position.

7. A relatively small casing for a high speed miniature centrifuge comprising: a base; side walls extending upwardly from the base; a cover, pivotal means for pivotally mounting said cover on said side walls between a closed position and an open position; a centrifuge in said casing; centrifuge mounting means for mounting said centrifuge in the casing whereby said casing with centrifuge is lightweight and portable; a latch means coupled with said cover and said side walls and extending therebetween to latch said cover to said side walls when said cover is in said closed position; means for actuating said latch to unlatch said cover from said walls so that said cover is permitted to be pivoted to said open position; a pivotal assembly coupled with said cover and said side walls and being therebetween permitting said cover to be pivoted between said open and closed position; means including surfaces of portions of the cover for cooperating to provide a stop for determining said open position and preventing said cover from \being pivoted beyond said open position from said closed position; and modular means on said casing for permitting said casing to be detacha-bly coupled with another like casing in Sldfi-bY-Slds'i relationship as modules of a multiple module system and to a module of said system other than a like centrifuge casing.

8. A modular system for blood prothrombin and coagulation time determinations comprising in combination: a plurality of modular units; at least one of said modular units including a relatively small casing and a high speed miniature centrifuge, said centrifuge being in said casing for separating whole blood by centrifuging, said casing comprising a base, side walls extending upwardly from said base, a cover, cover supporting means for supporting said cover on said side walls between a closed position and an open position, centrifuge mounting means for mounting said centrifuge in the casing, modular means on said casing and also forming part of other of said modular units for permitting said one of said modular units to be detachably coupled with other of said modular units of said system.

9. A relatively small casing for a high speed miniature centrifuge comprising: a base, side walls extending upwardly from the base; a cover; pivotal means for pivotally mounting said cover on said side walls between a closed position and an open position; a centrifuge head and motor in said casing; centrifuge motor mounting means for mounting said centrifuge motor in the casing whereby said casing with centrifuge head and motor is lightweight and portable; a latch means coupled with said cover and said side walls and extending therebetween to latch said cover to said side walls when said cover is in said closed position; handle means extending from the cover for cooperating in unla-tching said cover from said walls so that said cover is permitted to be pivoted to said open position; and quick-disconnect releasable locking means between said head and motor for releasably locking said head to said motor thereby permitting removal of the head from the motor when said cover is in said open position.

' 10. The invention in accordance with claim 9 wherein the quick-disconnect releasable locking means includes a shifitable pressure plate mounted within the casing and being in a first position and upon actuation being adapted to be shifted to a second position; and a spring biased against said plate internally of said casing urging said plate to said first position and when the plate is shifted to the second position, the bias of the spring is adapted to be overcome.

References Cited by the Examiner UNITED STATES PATENTS 540,854 6/1895 Choate.

540,875 6/1895 Price. 1,659,474 2/ 1928 Siemann 192136 1,761,943 6/1930 Summers et al. 1,844,008 2/1932 Grauss 210-94 X 1,951,079 3/1934 Zihlman.- 2,004,064 6/1935 Jordan et a1. 210-146 2,200,748 5/1940 Keil 312284 2,372,007 3/ 1945 Kroenlein 15327 X 2,376,449 5/ 1945 Oliver 220-82 X 2,592,596 4/ 1952 Pengelly 210-94 X 2,733,926 2/1956 Colton 27975 2,783,938 3/1957 Grelatet al 233-26 X 2,860,404 11/1958 Alden 312-411 2,867,834 1/1959 Kelly 15-327 2,913,26 11/1959 Zajac 285277 2,987,365 6/1961 Simpson 312-111 3,069,191 12/1962 De Pew 24-211 X 3,085,415 4/1963 Gosnell 6827 X 3,096,283 7/1963 Hein 23320 3,104,903 9/1963 Futch et'al.

M. CARY NELSON, Primary Examiner.

ROBERT F. BURNETT, Examiner. 

1. A RELATIVELY SMALL CASING FOR A HIGH SPEED MINIATURE CENTRIFUGE COMPRISING: A BASE; SIDE WALLS EXTENDING UPWARDLY FROM THE BASE; A COVER; PIVOTAL MEANS FOR PIVOTALLY MOUNTING SAID COVER ON SAID SIDE WALLS BETWEEN A CLOSED POSITION AND AN OPEN POSITION; A CENTRIFUGE IN SAID CASING; CENTRIFUGE MOUNTING MEANS FOR MOUNTING SAID CENTRIFUGE IN THE CASING WHEREBY SAID CASING WITH CENTRIFUGE IS LIGHTWEIGHT AND PORTABLE; A LATCH MEANS COUPLED WITH SAID COVER AND SAID SIDE WALLS AND EXTENDING THEREBETWEEN TO LATCH SAID COVER TO SAID SIDE WALLS WHEN SAID COVER IS IN SAID CLOSED POSITION; ARM MEANS COUPLED WITH SAID LATCH FOR ACTUATING SAID LATCH TO UNLATCH SAID COVER FROM SAID WALLS SO THAT SAID COVER IS PERMITTED TO BE PIVOTED TO SAID OPEN POSITION; AND A LINK ASSEMBLY COUPLED WITH SAID COVER AND SAID SIDE WALLS AND EXTENDING THEREBETWEEN PERMITTING SAID COVER TO BE PIVOTED BETWEEN SAID OPEN AND CLOSED POSITION, AND MEANS INCLUDING SURFACES OF SAID LINK 